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SS.SMx.CMx
Circalittoral mixed sediment

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Habitat (physical) description

Distribution

 Salinity: Full (30-35 ppt) 
 Wave exposure: Moderately exposed, Sheltered, Very sheltered 
 Tidal streams: Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible) 
 Substratum: Mixed sediment (with stones and shells) 
 Zone: Circalittoral 
 Depth Band: 5-10 m, 10-20 m, 20-30 m, 30-50 m 
 Other Features:  

Download comparative physical and biological data. The comparative tables enable a rapid comparison of the species composition and principal physical characteristics between a given set of biotopes.

Previous code

This biotope occurred in previous versions of the classification as:
CMX - Version: 97.06

Distribution of habitat SS.SMx.CMx  Circalittoral mixed sediment
Distribution of habitat SS.SMx.CMx Circalittoral mixed sediment, based on records on the UK Marine Recorder database and EUSeaMap. Red dots represent records on which the biotope is based. Blue dots show other certain records, black dots show records tentatively assigned to this biotope. Yellow areas show level 2 and 3 sublittoral and deep-sea habitats prediced by EUSeaMap within UK waters.

Biotope description

Mixed (heterogeneous) sediment habitats in the circalittoral zone (generally below 15-20m) including well mixed muddy gravelly sands or very poorly sorted mosaics of shell, cobbles and pebbles embedded in or lying upon mud, sand or gravel. Due to the variable nature of the seabed a variety of communities can develop which are often very diverse. A wide range of infaunal polychaetes, bivalves, echinoderms and burrowing anemones such as Cerianthus lloydii are often present in such habitat and the presence of hard substrata (shells and stones) on the surface enables epifaunal species to become established, particularly hydroids such as Nemertesia spp and Hydrallmania falcata. The combination of epifauna and infauna can lead to species rich communities. Coarser mixed sediment communities may show a strong resemblance, in terms of infauna, to biotopes within the SCS complex. However, infaunal data for this biotope complex is limited to that described under the biotope MysThyMx, and so are not representative of the infaunal component of this biotope complex.

Situation

No situation data available.

Temporal variation

No temporal data available.

Similar biotopes

Not applicable or unknown.

Characterising Species

Taxa Frequency Typical Abundance % Contribution to similarity Abundance (no.2)
Hydrallmania falcata O
Nemertesia antennina O
Nemertesia ramosa O
Alcyonium digitatum O
Cerianthus lloydii F
Urticina felina O
Nemertea C 2 31
Nematoda F 3 480
Pholoe inornata F 2 103
Glycera alba A 1 23
Goniada maculata C 2 27
Nephtys C 1 38
Nephtys hombergii C 2 38
Lumbrineris gracilis C 4 155
Scoloplos armiger A 3 90
Levinsenia gracilis C 1 67
Prionospio fallax A 8 492
Spiophanes bombyx F 2 75
Chaetozone setosa C 4 141
Mediomastus fragilis C 2 147
Scalibregma inflatum C 2 65
Galathowenia oculata F 1 74
Owenia fusiformis C 2 29
Terebellides stroemi A 2 32
Terebellidae O
Lanice conchilega O
Pomatoceros triqueter O
Ampelisca tenuicornis F 2 111
Eudorella truncatula A 1 37
Pagurus bernhardus O
Liocarcinus depurator O
Buccinum undatum O
Modiolus modiolus O
Pecten maximus O
Thyasira flexuosa C 7 375
Mysella bidentata F 5 249
Phaxas pellucidus C 1 28
Abra alba C 2 191
Chamelea gallina C 2 44
Flustra foliacea O
Phoronis C 2 149
Crossaster papposus R
Asterias rubens O
Ophiothrix fragilis C
Ophiocomina nigra F
Amphiura filiformis A 1 86
Ophiura albida F
Echinus esculentus O
Psolus phantapus O
Thyone fusus O
Corallinaceae O

Example photographs of biotope

No characteristic photos currently available. If you are able to provide a photograph of this biotope please contact .


Version 15.03 of the classification adds a deep-sea section to version 04.05; therefore superseding version 04.05, 97.06 and 03.02.

This online classification should be cited as:

JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed]. Available from: jncc.defra.gov.uk/MarineHabitatClassification

Information from the shallower section (up to sublittoral sediment, taken from Version 04.05) be cited as the report accompanying Version 04.05, as follows:

CONNOR, D.W., J.H. ALLEN, N.GOLDING, K.L.HOWELL, L.M. LIEBERKNECHT, K.O. NORTHEN AND J.B. REKER (2004) The Marine Habitat Classification for Britain and Ireland Version 04.05. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISBN 1 861 07561 8


Information from the deep-sea section (added in March 2015) should be cited as the report accompanying the deep-sea section, as follows:

PARRY, M.E.V., K.L. HOWELL, B.E. NARAYANASWAMY, B.J. BETT, D.O.B. JONES, D.J. HUGHES, N. PIECHAUD, T.D. NICKELL, H. ELLWOOD, N. ASKEW, C. JENKINS and E. MANCA (2015) A Deep-sea Section for the Marine Habitat Classification of Britain and Ireland. JNCC report 530. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISSN 0963 8901